Ajay Kumar at 05:00, 23 August 2023

2023-08-23T05:00:15Z

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{{Short description|Soils formed in volcanic ash and containing glass and amorphous colloidal materials}}
{{Infobox soil
|name=Andisol
|alternative_name=[[Andosol]]
|image=Andisol profile.jpg
|image_size=250px
|image_caption=an Andisol profile
|classification_system=[[USDA soil taxonomy]], [[World Reference Base for Soil Resources]]
|profile=ABwC
|parent_material=[[tephra]]
}}

In [[USDA soil taxonomy]], '''Andisols''' are [[soils]] formed in [[volcanic ash]] and defined as soils containing high proportions of [[glass]] and amorphous [[colloid]]al materials, including [[allophane]], [[imogolite]] and [[ferrihydrite]].<ref>{{cite web| url= http://soils.usda.gov/technical/classification/orders/andisols.html| title= Andisols| work= National Resource Conservation Service| publisher= [[United States Department of Agriculture]]| access-date= 2006-05-14| archive-url= https://web.archive.org/web/20060509223324/http://soils.usda.gov/technical/classification/orders/andisols.html| archive-date= 2006-05-09| url-status= dead}}</ref> In the [[World Reference Base for Soil Resources]] (WRB), Andisols are known as [[Andosol]]s.<ref>{{Cite web|url = http://www.fao.org/3/i3794en/I3794en.pdf|title = World Reference Base for Soil Resources 2014, Update 2015|author=IUSS Working Group WRB|year = 2015|publisher = World Soil Resources Reports 106, FAO, Rome}}</ref>

Because they are generally quite young, Andisols typically are very fertile except in cases where [[phosphorus]] is easily fixed (this sometimes occurs in the tropics). They can usually support intensive cropping, with areas used for wet [[rice]] in [[Java]] supporting some of the densest populations in the world. Other Andisol areas support crops of [[fruit]], [[maize]], [[tea]], [[coffee]] or [[tobacco]]. In the Pacific Northwest USA, Andisols support very productive [[forest]]s.

Andisols occupy about 1% of the global ice-free land area. Most occur around the [[Pacific Ring of Fire]], with the largest areas found in central [[Chile]], [[Ecuador]], [[Colombia]], [[Mexico]], the [[Pacific Northwest]] [[United States|US]], [[Japan]], Java and [[New Zealand]]'s [[North Island]]. Other areas occur in the [[Great Rift Valley, Kenya]], [[Italy]], [[Iceland]] and [[Hawaii|Hawai{{okina}}i]].

[[Fossil]] Andisols are known from areas far from present-day volcanic activity and have in some cases been dated as far back as the [[Mesoproterozoic]] 1.5 billion years ago.<ref>{{cite web |url=http://grunwald.ifas.ufl.edu/Nat_resources/soil_orders/andisols.htm |first=Sabine |last=Grunwald |title=Andisols |work=Soil & Water Sciences |publisher=[[University of Florida]] | access-date =2006-05-14 |archive-url=https://web.archive.org/web/20060916044155/http://grunwald.ifas.ufl.edu/Nat_resources/soil_orders/andisols.htm|archive-date=2006-09-16 }}</ref><ref>{{cite web |url=http://soils.ag.uidaho.edu/soilorders/andisols.htm |title=Andisols |work=Soil and Land Sciences Division |publisher=[[University of Idaho]] |access-date=2006-05-14 |archive-url=https://web.archive.org/web/20090309093838/http://soils.ag.uidaho.edu/soilorders/andisols.htm |archive-date=2009-03-09 |url-status=dead }}</ref>

==Suborders==

*'''Aquands''' – Andisols with a water table at or near the surface for much of the year.
*'''Gelands''' – Andisols of very cold climates (mean annual temperature <0 °C).
*'''Cryands''' – Andisols of cold climates.
*'''Torrands''' – Andisols of very dry climates.
*'''Ustands''' – Andisols of semiarid and sub humid climates.
*'''Udands''' – Andisols of humid climates.
*'''Xerands''' – temperate Andisols with very dry summers and moist winters.
*'''Vitrands''' – relatively young Andisols that are [[soil texture|coarse-textured]] and dominated by glass.

== See also ==
*[[Pedogenesis]]
*[[Pedology (soil study)]]
*[[Soil classification]]

== References ==
{{reflist}}

{{Soil type}}

[[Category:Pedology]]
[[Category:Types of soil]]
[[Category:Volcanic soils]]

Andisol - Revision history

Ajay Kumar at 05:00, 23 August 2023